Now that the crisis with Fukushima Dai-ichi Unit 1 seems at least momentarily averted, media attention has been directed to Fukushima Dai-ichi Unit 3 and other reactors with coolant problems which are reportedly in near partial or complete meltdown. But what is a reactor meltdown, and does it represent the sort of end of the world horror stories that anti-nuclear "experts" who appear on television tell us about?
Japan has suffered a natural disaster of almost unimaginable. Today millions of people in Japan are struggling to find the basic necessities of life, food, water, shelter. Tens of thousands of people are likely dead, and the scale of damage and destruction has not been seen in Japan since World War II bombing raids leveled many Japanese cities. Is the focus on Japanese reactors by the news media appropriate, or an exaggerated diversion from a human tragedy of almost unimaginable proportions?
The worst thing that we could imagine is a core meltdown and the escape of gaseous radio isotopes and volatile chemical compounds containing radioactive fission products. The release into the atmosphere of radioactive fission products in a reactor accident is of course the worst possible consequence of any core meltdown, but how much radioactive materials are we talking about, and how dangerous are they? Oak Ridge National Laboratory scientists researched nuclear safety during the 1960's until their research was shut down by an Atomic Energy Commission bureaucrat, Milton Shaw in the mid 1960's. The Oak Ridge scientists looked at what fission products were likely to escape into the atmosphere, they concluded, that much of the escaping radioactive materials would be rare gases, for example various Xenon isotopes, that would rapidly dissipate in the atmosphere and would pose almost no health hazard because they are either biologically inactive, or not dangerous if bonded to living tissue. Halogens including various isotopes of radioactive Iodine form volatile compounds inside an overheating reactor. Some are likely to be released into the air, even if outer barriers to fission product release are intact. Various isotopes of Iodine are especially hazardous because iodine does form chemical bonds in living tissues. Indeed all of the known long term health consequences of the Chernobyl fire and subsequent fallout of radioactive material were due to radioactive iodine exposure. This is important information, because the health consequences of radioactive iodine exposure can be largely avoided if people who are exposed to radioactive iodine fallout are immediately given non-radioactive iodine-127 tablets.
Unlike the AEC Bureaucrat, Milton Shaw, Oak Ridge reactor chemists, including my father regarded nuclear safety research as providing
highly useful information.They concluded,
it is now recognized that the hazard of reactor accidents can be fully evaluated only through sophisticated accident simulation experiments in facilities such as the Containment Research Installation (ORNL), the Containment Systems Experiment (Battelle Northwest), and the Loss-of-Fluid Test (Phillips-Idaho).
What the Oak Ridge scientists were saying is that we can only tell what dangers a nuclear meltdown pose by melting down a reactor and observing what happened. But according to Robert Pool:
Milton Shaw, the head of the AEC's Division of Reactor Development and Technology, was convinced that such safety research was reaching the point of diminishing returns. An old Rickover protege, Shaw saw light-water reactors as a mature technology. The key to the safety of commercial power plants, he thought, was the same thing that had worked so well for the navy reactor program: thick books of regulations specifying every detail of the reactors, coupled with careful oversight to make sure the regulations were followed to the letter.Pool here has captured the problems with Shaw's vision, which unfortunately did not include natural disasters like 8.9 earthquakes, or tsunamis, and Shaw had the last word.
Since Shaw refused to let the scientists conduct their nuclear meltdown experiment, the public has exaggerated fears relative to nuclear safety which television, newspapers, and the renewable energy lobby loves to exploit.
Light Water Reactor meltdowns are not very dangerous to the public, even if the meltdown is not contained, and chances are high in most instances that most meltdowns will be contained. One class of reactor, the Molten Salt Reactor was safely operated in test condition for thousands of hours with its fuel completely molten. Although United States scientists did not get the opportunity to experimentally melt a reactor core down, they got a chance to observe several nuclear meltdowns. On October 1, 1966, the core of the Fermi 1 reactor, located at Lagoona Beach, Michigan, close to Detroit, underwent a limited meltdown of several sub assemblies. The consequences were not monumental, and the reactor was repaired, and briefly put back into service. No one was injured, received an excessive radiation exposure or was killed.
Scientists got another chance to observe a reactor after a partial meltdown in 1979 when the core of The Three Mile Island Unit 1 reactor underwent a partial meltdown. Again the consequences of the Three Mile Island incident was hardly the disaster that Greenpeace, and the renewable energy lobby would have us believe. No one was killed, no one was exposed to high levels of radiation and no one was injured by The Three Mile Island Accident. In contrast an explosion at a Middletown, Connecticut natural gas fired power plant in 2010, killed 6 people, while a dozen more received hospital treatment for injuries. As with the Three Mile Island disaster, the Middletown power plant was effectively destroyed. Question: "which was worse, the Kleen Energy power plant blast, that killed six people, and injured a dozen more and destroyed the power plant, or the Three Mile Island accident which destroyed a power plant but which did not hurt anyone. The Renewable Energy Lobby takes leave from common sense by answering Three Mile Island.
The Renewable Industry lobby will answer, but what about Chernobyl? First, the Chernobyl reactor had primitive, World War II type nuclear safety features, that were clearly inadequate. The Chernobyl reactor lacked the inner steel containment vessel and the outer concrete containment building which American and Japanese reactors all have. In addition there were dangerous flaws, that were unique to Soviet reactors, in the Chernobyl reactor design. Because of the lack of containment, and features of the accident that were due to Soviet reactor design flaws, the scale of radioactive fall out from Chernobyl was far greater than the scale of radioactive fallout from western Light water reactors.
But given the Chernobyl accident, the consequences were far from horrific, although they seemed so at the time. A group of very reputable agencies, including the World Health organization says,
the majority of the residents of areas designated as ‘contaminated’ in Belarus, Russia and Ukraine (over 5 million people) received relatively low whole-body doses of radiation, not much higher than doses due to natural background radiation.The report adds,
Childhood thyroid cancer caused by radioactive iodine fallout is one of the main health impacts of the accident. Doses to the thyroid received in the first few months after the accident were particularly high in those who were children at the time and drank milk with high levels of radioactive iodine. By 2002, more than 4000 thyroid cancer cases had been diagnosed in this group, and it is most likely that a large fraction of these thyroid cancers is attributable to radioiodine intake.
Apart from the dramatic increase in thyroid cancer incidence among those exposed at a young age, there is no clearly demonstrated increase in the incidence of solid cancers or leukaemia due to radiation in the most affected populations.
Most of the health consequences of the Chernobyl accident were psychological, and can be attributed to a fear of the unknown, in this case the unknown referring to the health consequences of exposure to relatively small radiation doses. Yet even the only health consequence, Thyroid cancer, is treatable, although any illness is undesirable.
Question: Which is more dangerous, the Chernobyl reactor or a chemical plant. Answer the chemical plant of course. As a consequence to one chemical plant accident in Bhopal, India, at least 3787 people are officially estimated to have died, and 100,000 more people developed symptoms of chemical exposure, as a result of the disaster. Once again the Renewable Energy lobby takes leave of its senses, by answering Chernobyl. Apparently for organizations like Greenpeace, the 52 people who the World Health Organization say died as the result of the Chernobyl accident are far more dead than the 3787 people who died as the result of the Bhopal disaster.
The Chernobyl accident had consequences that were far worse than could be expected from a Light Water Reactor core meltdown. The core of the Chernobyl reactor exploded blowing off the roof of the Chernobyl Reactor. Then the core, destroyed by the explosion, molten hot, and exposed to air, caught fire. As radioactive materials burned, they were lifted into the air by the heat of the fire, and rose far above ground level. In contrast most of the radioactive materials in the core of a light water reactor will stay where they are, even if the core vessel and containment building have been destroyed. The Three Mile Island accident demonstrated that radioactive gases were quickly diluted in open air, while most of the tiny amount of volatile fusion products probably quickly precipitate out of the air. No health problems were ever noted as a consequence of the iodine release.
I much add that I am not advocating a blasé attitude toward nuclear safety. Quite the contrary, I advocate that reactors be built to the highest safety standards possible, but when compared to other energy technologies, including even solar and wind, reactors are very safe. Thus, from the standpoint of safety, reactors should be preferred over other energy technologies because they are safer. This should be the end of the story, but the renewable energy lobby has successfully sold newspaper and television reporters on their nuclear boogeyman story.
UPDATE: Japanese authorities are now reporting that sea water is being injected into Fukushima Dai-ichi Unit 3.
UPDATE 2 (3/14/11):
People are beginning to use the term "nuclear disaster," to describe the Japanese reactor problems which are actually a part of the aftermath to a real and huge disaster, the Japanese earthquake/tsunami. The word disaster is used in this case in a quite loose fashion. The normal characteristics of a disaster include loss of life, wide scale material damage to property, and undesirable changes to the environment. It is not clear that the problems at the Japanese reactors minimally qualify as a disaster. There has been no damage to property outside the reactors themselves, and no loss of life. The real disaster was the earthquake/tsunami event of which the reactor problems are consequences. Thus the use of the term 'nuclear disaster" seems inappropriate.